1. Field of the Invention
The present invention generally relates to a technology for securing high reliability by performing a preventive measure against a failure of a hard disk device and for assuring a rigorous data security in a disk array apparatus.
2. Description of the Related Art
A volume of data processed in a data processing system has become larger and larger and a disk array has been increasingly used as a storage device in the data processing system. The disk array can include a plurality of hard disk devices, which are grouped into a virtual hard disk device. Therefore, the disk array can realize a larger capacity.
In the disk array, data redundancy such as mirroring is generally obtained for securing reliability. The mirroring is a method of storing data in the hard disk devices. Due to the mirroring, even if one of the hard disk devices in the disk array gets damaged, processing of the data can be carried on by using data stored in another hard disk device.
A technique for securing reliability of the disk array is disclosed in Japanese Unexamined Patent Application Publication H11-345095. According to the technique, a disk array apparatus includes a group of hard disk devices (a disk array) and a spare disk. When a failure is predicted in one of the hard disk devices, data in a failure-predicted hard disk device is transferred to the spare disk. Then the spare disk can be grouped into the disk array.
However, above conventional technique has a problem regarding data security. When the failure-predicted hard disk device is removed from the disk array and replaced with a new hard disk device by a service engineer, the data remains in the failure-predicted hard disk device, which causes data-leakage from the failure-predicted hard disk device.
If there is an accident or a fraud on the failure-predicted hard disk device, confidential data such as trade secrets or customer information can be stolen from the failure-predicted hard disk device. Recently, an Act on the Protection of Personal Information has been enforced in Japan. There has been an increasing demand for securing data in companies or other entities. Therefore, a possibility of the data-leakage with the conventional technique is a critical problem.